Readers and computer program products that cooperate with single-use external dosimeters for use in radiation therapies

ABSTRACT

Methods, systems, devices, and computer program products include positioning single-use radiation sensor patches that have adhesive means onto the skin of a patient to evaluate the radiation dose delivered during a treatment session. The sensor patches are configured to be minimally obtrusive and operate without the use of externally extending power cords or lead wires.

RELATED APPLICATION

This application is a divisional of U.S. patent application Ser. No.12/474,908, filed May 29, 2009, which is a divisional of U.S. patentapplication Ser. No. 10/303,591, filed Nov. 25, 2002, which claimspriority to U.S. Provisional Patent Application Ser. No. 60/334,580,filed Nov. 30, 2001, the contents of which are hereby incorporatedherein by reference.

FIELD OF THE INVENTION

The present invention generally relates to the assessment orquantitative evaluation of the amount of radiation delivered to apatient undergoing radiation therapy.

RESERVATION OF COPYRIGHT

A portion of the disclosure of this patent document contains material towhich a claim of copyright protection is made. The copyright owner hasno objection to the facsimile reproduction by anyone of the patentdocument or the patent disclosure, as it appears in the Patent andTrademark Office patent file or records, but reserves all other rightswhatsoever.

BACKGROUND OF THE INVENTION

Conventionally, radiation therapy is delivered over a successive seriesof radiation treatment sessions. High-energy photons and/or electronsare carefully directed and/or focused from an ex vivo radiation sourceso that they travel into a targeted treatment area in a patient's body.The size, shape, and position of the treatment area (typically where atumor is or was) as well as its anatomical location in the body and itsproximity to sensitive normal tissues are considered when generating aparticular patient's treatment plan. That is, the treatment is plannedso as to deliver a suitably high dose of radiation to the tumor ortargeted tissue while minimizing the dose to nearby sensitive tissuethat typically cannot be completely avoided. Directing radiation intonon-affected regions may produce undesired side effects particularly asit relates to tissue that may be sensitive to certain dosages ofradiation. Unfortunately, even when the patient plan is carefullyconstructed to account for the location of the cancerous tissue and thesensitive non-affected regions, even small errors in set-up due to beamangle or patient position during delivery of the radiation therapy caninadvertently misdirect radiation into those regions or can influencethe dose amount that is actually received by the targeted tissue.Further, the demand for radiation treatment equipment is typicallyrelatively high and this demand may limit the set-up time allowed orallocated in the treatment room between patients.

In the past, implantable devices for oncology applications have beenproposed to evaluate the radiation dose amount received in vivo at thetumor site. See e.g., U.S. Pat. No. 6,402,689 to Scarantino et al., thecontents of which are hereby incorporated by reference herein. Measuringthe radiation at the tumor site in vivo can provide improved estimatesof doses received. However, for certain tumor types or situations, askin-mounted or external surface radiation dosimeter maybe desirable andsufficient for clinical purposes.

Conventional external or skin-mounted radiation dosimeter systems usesemiconductor circuitry and lead wires that power/operate thedosimeters. These types of dosimeters are available from Scandatronicsand/or IBA (“Ion Beam Applications”) having an internationalheadquarters location in Belgium. While these radiation dosimetersystems may provide radiation dose estimations, they can, unfortunately,be relatively expensive. Further, these types of dosimeters are used fora plurality of patients potentially raising sterility or cleanlinessproblems between patients. Conventional dosimeter systems may alsorequire substantial technician time before and during the radiationsession. For example, conventional dosimeter systems need to becalibrated before the radiation session may begin. In addition, the leadwires can be cumbersome to connect to the patients and may requireexcessive set-up time as the technician has to connect the lead wires torun from the patient to the monitoring system and then store the leadwire bundle between patient treatment sessions. Therefore, techniciansdo not always take the time to use this type of system, and noconfirmation estimate of the actual radiation delivered is obtained.

Other radiation sensors include thermo-luminescent detectors (TLD's).However, while TLD detectors do not require wires during operation, theyare analyzed using a spectrophotometer (that may be located in anoffsite laboratory) and are not conducive to real-time readings.

In view of the foregoing there remains a need for improved economicaland easy to use radiation dosimeters.

OBJECTS AND SUMMARY OF THE INVENTION

It is therefore an object of the present invention to provide acost-effective surface mount radiation dosimeter that can be used toevaluate the radiation dose delivered to a patient undergoing radiationtherapy.

It is a further object of the present invention to provide economicmethods and devices that can reduce labor set-up time in the radiationtreatment chamber over conventional evaluation methods and devices.

It is an additional object of the present invention to provide a memorystorage device on the patch to record the dose history of the patch.This memory storage device may be queried at any time in order to obtaina record of the dose applied to the patch. Other information, such aspatient identification, time, date, hospital, therapist, state of thedevice, dosed/undosed and calibration data may be stored in the memorystorage device.

It is an additional object of the present invention to provide aneconomic method of determining the amount of radiation delivered to anoncology patient in situ.

These and other objects can be satisfied by the present invention by adisposable, single-use skin mounted radiation dosimeter that has aself-contained package that is small, adhesively attachable to the skinof the patient, and operates in a relatively easy to operate and readmanner without requiring the use of lead wires.

Certain embodiments of the present invention are directed to methods formonitoring radiation doses administered to patients undergoing radiationtreatments. The methods include the steps of: (a) releasably securing atleast one single-use dosimeter sensor patch onto the skin of the patientsuch that the patch is self-contained and devoid of leads extendingtherefrom; (b) administering radiation to the patient in a firsttreatment session; (c) contacting the sensor patch with a dose-readerdevice after the administering step to obtain data associated with achange in an operational parameter in the dosimeter sensor patch; and(d) determining the radiation dose received by the patient during theadministering step based on the change in the operational parameter.

In some embodiments, the sensor patch may be pre-dosed and/or calibratedbefore the sensor patch is secured to the patient. The obtained data maybe stored in an electronic storage device provided on the sensor patchitself The storage device may be, for example, an EEPROM. Otherinformation, such as the patient's name, the doctor's name, the testdate and the like, may also be stored in the storage device provided onthe sensor patch. Alternatively, the data can be stored on a computerreadable memory integrated on a physical record sheet that can be placedin the patient's file.

Other embodiments are directed to systems for monitoring radiationadministered to a patient during a therapeutic treatment. The systemcomprises: (a) at least one disposable single-use dosimeter patch, thepatch comprising a body holding a circuit with at least one MOSFET andan external reader contact region thereon, the MOSFET(s) having anassociated threshold voltage that changes when exposed to radiation, thebody comprising opposing upper and lower primary surfaces; and (b) anexternal portable dose-reader being configured to make electricalcontact with the patch by physically engaging with the contact region onthe patch to obtain voltage threshold data corresponding to the doseamount of radiation exposure it is exposed to in use. During operation,the patch has a perimeter that is devoid of outwardly external leadwires.

In some embodiments, the patch includes a conformable resilient body.The lower primary surface may include a medical grade adhesive and thesensor patch may be pressed on to secure the sensor patch to thepatient. In other embodiments, an adhesive coverlay is applied over thesensor patch to secure the sensor to the patient. A portion or all ofthe sensor patch may be adapted to be inserted into the dose-reader totransmit the dose data and the dose-reader may similarly be adapted toreceive a portion or all of the sensor patch. Insertion of the sensorpatch into the reader electrically couples the sensor to the reader andallows the reader to receive the radiation dose data from the sensorpatch. The sensor patch may also include an electronic storage device inelectrical communication with the sensor. The sensor patch may then bepre-dosed and/or calibrated before the radiation session. Data may bedownloaded from the memory of the sensor patch to a remote computerand/or a computer application using the electrical coupling of thesensor patch and the dose-reader.

In certain embodiments, the at least one dosimeter patch is a pluralityof discrete sensor patches and the reader is configured to seriallycontact with each respective sensor patch to obtain the thresholdvoltage value associated therewith.

A sheet of sensor patches may be pre-dosed and/or calibratedsimultaneously or individually before the sensor patches are secured tothe patient. The calibration and/or pre-dosing may be performed at theoriginal equipment manufacturer (OEM) or at the actual test site. Thesheet of sensor patches may include about 30 to about 100 sensors. Thesensors may also be provided in a high density array of sensors where somany sensors are provided in a certain area of the high density array,for example, multiple sensors may be provided per square inch or per 3by 3 inch regions of the high density array.

Still other embodiments are directed to sets of disposable single-useradiation dosimeter patches. The sets comprise a plurality of discretedisposable single-use dosimeter patches, each patch comprises aconformable body holding a circuit with an operational electroniccomponent that changes a parameter in a detectable predictable mannerwhen exposed to radiation, the body comprising opposing upper and lowerprimary surfaces and the dosimeter patch, in use and positioned on thepatient, is devoid of externally hanging lead wires.

The operational electronic component may be a radiation sensitive biasedMOSFET or MOSFETs (such as MOSFET pairs) and the detectable operationalparameter that changes can be the MOSFET threshold voltage(s).Furthermore, a medical grade adhesive may be supplied on the lowerprimary surface of the sensor body such that the sensor may be adheredto the patient's skin. In certain embodiments, an adhesive coverlay maybe provide over the body of the sensor to secure the sensor to thepatients skin.

Another embodiment is directed to a computer program product forevaluating a radiation dose delivered to a patient. The computer programproduct comprises a computer readable storage medium having computerreadable program code embodied in the medium. The computer-readableprogram code comprises: (a) computer readable program code for receivingpre-irradiation threshold voltage data associated with a plurality ofdisposable sensor patches; (b) computer readable program code foraccepting data from a reader configured to electrically serially contacteach of the plurality of disposable sensors for a short time; and (c)computer readable program code for determining the voltage thresholdshift of the disposable sensor patches after radiation to determine theradiation exposure.

In still further embodiments of the present invention, a dose-reader maybe adapted to receive a sensor patch in a sensor port. The sensor patchis also adapted to be inserted in the sensor port. The dose-reader canbe a pocket or palm sized portable device. The dose-reader may alsoinclude a communications port, for example, a universal serial port(USB), RS 232 and the like, for downloading obtained data to a computerapplication or remote computer. The dose-reader functionality may beincorporated into a personal digital assistant (PDA) or other pervasivecomputer device.

In further embodiments the sensor patch may be configured to communicatewith the dose-reader wirelessly. For example, the sensor patch and thedose-reader may both be equipped with an radio frequency (RF) interfaceso that information may be shared between the two devices.

The foregoing and other objects and aspects of the present invention areexplained in detail in the specification set forth below.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a schematic illustration of a patient undergoing radiationtreatment according to embodiments of the present invention.

FIG. 2 is a block diagram of operations for monitoring patientsundergoing radiation treatments according to embodiments of the presentinvention.

FIGS. 3A and 3B are illustrations of sets of disposable dosimeterpatches according to embodiments of the present invention.

FIG. 3C is an anatomical map of sensor location according to embodimentsof the present invention.

FIG. 4 illustrates an exemplary patient information form according toembodiments of the present invention.

FIGS. 5A and 5B are schematic illustrations of sensor placement on apatient according to embodiments of the present invention.

FIG. 6 is a schematic illustration of embodiments of a reader contactingthe sensor to obtain the radiation dosage data according to embodimentsof the present invention.

FIG. 7 is a schematic illustration of further embodiments of a readerreceiving the sensor in a sensor port to obtain the radiation dosagedata according to embodiments of the present invention.

FIG. 8A is a greatly enlarged side view of a disposable radiationdosimeter according to embodiments of the present invention.

FIG. 8B is a top view of the dosimeter shown in FIG. 8A.

FIG. 8C is a partial cutaway view of a probe head for a reader accordingto embodiments of the present invention.

FIG. 9A is a schematic of embodiments of a sensor patch with a circuitthereon according to embodiments of the present invention.

FIG. 9B is a schematic of further embodiments of a sensor patch with acircuit thereon according to embodiments of the present invention.

FIG. 9C is a schematic of further embodiments of a sensor patch with acircuit thereon according to embodiments of the present invention.

FIG. 9D is a schematic of further embodiments of a sensor patchaccording to embodiments of the present invention.

FIG. 9E is a schematic of further embodiments of a sensor patchaccording to embodiments of the present invention.

FIG. 10A is a schematic illustration of a sheet of sensors according toembodiments of the present invention.

FIG. 10B is yet another schematic illustration of a sheet of sensorsaccording to embodiments of the present invention.

FIG. 10C is a further schematic illustration of a sheet of sensorsaccording to embodiments of the present invention.

FIG. 11 is a schematic of a circuit diagram of a MOSFET sensor with areader interface and an optional memory according to embodiments of thepresent invention.

FIG. 12A is a schematic of a threshold voltage reader circuit accordingto embodiments of the present invention.

FIG. 12B is a graph of the change in the threshold voltage value versusradiation dose according to embodiments of the present invention.

FIG. 13 is a graph of the threshold voltage dependence on Ids using thevoltage (V₀) of the reader illustrated in FIG. 12A.

FIG. 14A is a schematic of a circuit diagram with a MOSFET pair, theleft side of the figure corresponding to an irradiation operativeconfiguration and the right side of the figure corresponding to a readdose operative configuration, according to embodiments of the presentinvention.

FIG. 14B is a schematic of a circuit diagram with a MOSFET pair, theleft side of the figure corresponding to an irradiation operativeconfiguration and the right side of the figure corresponding to a readdose operative configuration, according to other embodiments of thepresent invention.

FIG. 15A is a schematic of a system or computer program product forestimating radiation based on data taken from a point contact-readerdata acquisition system according to embodiments of the presentinvention.

FIG. 15B is a block diagram illustrating a reader device according toembodiments of the present invention.

FIG. 15C is a block diagram illustrating a reader device according tofurther embodiments of the present invention.

FIG. 16 is a block diagram of a computer program having a radiationestimation module according to embodiments of the present invention.

FIG. 17 is a block diagram of a point-contact reader data acquisitionsystem according to embodiments of the present invention.

DESCRIPTION OF EMBODIMENTS OF THE INVENTION

The present invention will now be described more fully hereinafter withreference to the accompanying figures, in which preferred embodiments ofthe invention are shown. This invention may, however, be embodied inmany different forms and should not be construed as limited to theembodiments set forth herein. Like numbers refer to like elementsthroughout. In the figures, certain components, features, or layers maybe exaggerated for clarity. In the block diagrams or flow charts, brokenlines indicate optional operations, or features unless stated otherwise.

FIG. 1 illustrates an example of a radiation system 10 with a radiationbeam source 20 directed at a patient 50 having a tumor site. The patient50 can be positioned so as to be aligned and stationary with respect tothe beam 20 b (illustrated by the diverging dotted lines) during thetreatment. As such, the patient 50 can be arranged in any desiredposition depending on the direction of the beam, the location of thetumor, and the type of radiation therapy system employed. As shown, thepatient is reclined, substantially flat and face up on a table so thatthe beam 20 b is directed into the targeted tumor site in the body asthe patient undergoes radiation therapy in a treatment session.Typically, the patient will undergo a plurality of successive treatmentsessions over a treatment period. Each treatment session may be plannedto administer radiation doses of between about 1-2 Gray (100-200 cGy)with an overall treatment limit of about 35-80 Gray.

To help monitor or estimate the amount of radiation that is delivered tothe patient during a treatment session, at least one disposablesingle-use dosimeter sensor patch 30 can be positioned externally on theskin of the patient 50. As used herein, “single-use” is used to refer toa use for a single patient during a treatment session. The sensor patch30 may be episodically worn or continuously worn. It will be understoodthat a treatment session may include an active radiotherapyadministration during a single treatment session or serially spacedapart treatment sessions. The treatment session may have a duration ofminutes, hours, days and the like. Furthermore, a calibration doseobtained before the sensor patch 30 is positioned on a patient is not tobe considered the “single-use.”

As shown in FIG. 1, a plurality of sensor patches 30 are located both onthe front and back of the patient 50. The sensor patches 30 areconfigured to change an operational parameter in a predictable mannerthat correlates to radiation dose it receives, as will be discussedfurther below. The sensor patch 30 can be configured so as to beself-contained and discrete and devoid of dangling lead wires extendingto a remote power source or operating system during use and in positionon the patient. As such, a reader, for example, reader 75 (FIGS. 6 and7), can be configured to obtain the data from the sensor patch 30 by,for example, electrically contacting with each sensor patch 30 ofinterest.

As used herein, the reference number “75” will be used to refergenerally to a reader device according to embodiments of the presentinvention. Particular embodiments of a reader device 75 may be referredto using the reference number 75 and one or more primes attachedthereto. For example, particular embodiments of the reader device may bedenoted 75′ or 75″. This convention may similarly be used with respectto other features of the present invention. For example, the referencenumber “30” will be used to refer to particular embodiments of a sensorpatch herein. It will be understood that features discussed with respectto any embodiment of the present invention may be incorporated intoother embodiments of the present invention even if these features arenot discussed specifically with reference to each individual embodiment.

Referring to FIG. 2, operations that can be carried out to monitor theradiation dose that is delivered to a patient undergoing radiationtherapy are illustrated. At least one single-use disposable dosimetersensor patch can be releasably secured to the skin of the patient (block100). In certain embodiments, the sensor patch may be calibrated and/orpre-dosed before being attached to the patient (block 101). Thecalibration and/or pre-dosing of the sensor patch may be done on anindividual patch basis or many sensor patches may be calibrated and/orpre-dosed in batches simultaneously as discussed further below. Incertain embodiments, the patch(es) can be conveniently attached to thepatient in operation-ready condition before the patient enters theradiation treatment room or chamber (block 102) to limit or reduce theset-up time required or the “down-time” of the equipment or thetreatment room. In other words, the sensor patch or patches may besecured to the patient prior to his/her entry into the radiationtreatment room. A pre-irradiation or pre-dose measurement or reading ofdata associated with an operational parameter of the sensor patch(es) 30can be obtained prior to initiation of the radiation treatment (block105). The data can be obtained in situ, with the sensor patch(es) 30 inposition on the patient. Alternatively, the pre-dose data can beestablished prior to positioning the sensor patch(es) onto the subjectas discussed above and the data then transferred to the reader orassociated controller and/or computer at a desired time.

In certain embodiments of the sensor patch(es), the post-radiationreading can be taken when the patient leaves the treatment room toevaluate the dose delivered during the treatment session to limit theamount of room-use time. The sensor patches 30 can be removed from thepatient and then read by a handheld portable or a bench top reader. Inother embodiments, the reading can be obtained while the sensor patches30 remain on the patient. In certain particular embodiments, the readingmay be able to be obtained in situ during the treatment session (withoutremoving the sensor patch(es) from the patient) to provide real-timefeedback to the clinician estimating whether the desired dose is beingadministered to the patient. In certain embodiments, the temperature ofthe sensor patch (such as at a location adjacent the circuitry) or ofthe subject (skin or core body) can also be ascertained or obtained andtaken into account when calculating the radiation dose. In any event thedose reading can be obtained without requiring external powering orexternally applied biasing of the sensor patches 30 during the radiationtreatment.

In certain embodiments, a plurality of discrete sensor patches 30 can bepositioned to cover a region on the skin that is in the radiation beampath so as to reside over the tumor site. In particular embodiments, oneor more sensor patches 30 can also be positioned in radiation sensitiveareas of the body to confirm stray radiation is not unduly transmittedthereto. FIG. 2 illustrates that a sensor patch can be located at theneck over the thyroid when the tumor site is over the chest region. Assuch, sensitive regions include, but are not limited to, the thyroid,the spine, the heart, the lungs, the brain, and the like. In any event,referring again to FIG. 1, radiation is administered to the patient in afirst treatment session (block 110). Data associated with a change in anoperational parameter in the dosimeter sensor patch circuitry may beobtained from the sensor patch using a reader device (block 120) afteradministering the radiation to the patient (block 110). In certainembodiments, a sensor patch may be removed from the patient and insertedinto the reader device to transfer the data from the sensor patch. Infurther embodiments, the reader device may contact the sensor patch asdiscussed further below. The radiation dose received by the patient canbe determined based on the obtained data (block 125). The obtained dataas well as other information may be stored in a memory device includedon the sensor patch as described further below (block 130).

The sensor patch does not require lead wires extending from a remotepower source or computer system to operate. Instead, the sensor patch 30is configured to be a discrete patch (or a patch array of sensors) thatcan transmit or relay data upon contact with and/or insertion into areader device 75 and may store data in an electronic memory deviceincluded on the sensor patch. In certain embodiments, the sensor patch30 may be configured to communicate wirelessly with the reader 75. Theradiation dose received by the sensor patch 30 can be determined andused to estimate the dose received by the patient during the radiationtherapy session based on the data obtained by the reader. The readeritself can be a handheld portable unit that may or may not include wiresto connect with a remote controller or computer as will be discussedfurther below. In any event, the operations can be carried out for eachor a selected radiation treatment session. If the operations arerepeated for each treatment session, a cumulative amount of deliveredradiation can be estimated/confirmed to allow a clinician to evaluatewhether additional treatments are desired.

FIG. 3A illustrates that the sensor patches 30 can be provided in a kitor set 130 including a plurality of sensors 30 p. The plurality ofsensors 30 p may be configured in sufficient numbers or types for asingle patient or so as to be able to supply sensors across a pluralityof patients. In certain embodiments, a strip of six sensor patches 30can be packaged together as a set 130′ as shown in FIG. 15A. It iscontemplated that, depending on the treatment type, the treatmentlocation, the tumor site, and the like, different numbers of sensorpatches 30 may be used for different patients. Thus, if the sensor kit130 is sized for a single patient, the kit may include from about 2 toabout 10 or more sensor patches 30 that can be selectively chosen foruse by the clinician. Each sensor patch 30 can be sterilized and sealedin a sterile package or the kit 130 itself can be sized and configuredto hold a plurality of the sensor patches 30 p in a sterile packagethat, once opened, can be either used or discarded. Similarly, if thesensor kit 130 is sized for multi-patient use, then larger quantitiesmay be packaged individually, or in sets within the multi-patientpackage, together. The sterilization can be performed by heat orchemical exposure, such as by ethylene oxide sterilization. In certainembodiments, sterilization and/or sterile packaging may not be required.

As is also shown in FIG. 3A, each sensor patch 30 can be packaged withpre-irradiation characterizing data 132. This data 132 can be includedin optically or electronically readable formats such as in bar codeformat for the reader to be able to read without having the clinicianenter the information into a controller/computer. In certainembodiments, the data 132 may be included in a memory storage device 67,for example, an electrically programmable memory such as an electricallyerasable read only programmable memory (EEPROM), provided on each sensorpatch 30 p as discussed further below. The memory storage device 67 mayinclude information such as patient identification, time, date,hospital, therapist, state of the device, dosed/undosed sensor data andcalibration data. The memory storage device 67 may further be used tostore bias parameters and/or information with respect to measurementmethodology for each individual patch 30.

Each sensor patch 30 can have an individual calibration coefficient,dose data or characterizing data label located on the sensor patch 30 oras a corresponding label held with the package or kit 130. In otherembodiments, each sensor patch 30 produced in a common production run(off of the same wafer or chip) with substantially similarcharacterizing data may be packaged together and a single calibrationcharacterizing data or label 132 can be included with the set 130 orsets or production run. In certain embodiments, the calibration relatedcharacterizing data can include the pre-irradiation threshold voltagevalue of a metal-oxide semiconductor field-effect transistor(s)(MOSFET(s)) that is measured at an OEM and provided in or with thesensor patch set 130.

In certain embodiments, identifying indicia may be disposed on thesensor patches 30 to allow a clinician to easily visually identifyand/or account for the sensors used. For example, FIG. 3A illustratesthree discrete sensor patches labeled as 1F, 2F, and 3F as well as asensor with a pictorial representation of a heart 4F (other visualimages can also be used such as a yellow caution sign, other anatomicalsymbols, and the like). The heart or caution sensor patch 30s can bepositioned in a radiation sensitive area to detect the amount ofradiation delivered to that area. Typically, the radiation beam isadjusted to reduce the radiation exposure to sensitive areas and acaution-sensitive sensor patch 30s (or patches) can indicate whetheradjustments need to be made to reduce the detected exposure for each orselected treatment sessions. The sensor patches 30s used for sensitivedetection may be configured with increased sensitivity for enhanced doseresolution capability for measuring small, residual, or stray doses ofradiation (such as those located over critical organs which are not inthe treatment volume). For example, for “normal” single use sensors maybe configured to operate over a range of between about 50-500 cGy; the“high sensitivity” sensor might be configured to operate from about 1-50cGy. In particular embodiments, the circuit 30 c (FIG. 9A) for the highsensitivity sensor 30 s includes at least one radiation-sensitivefield-effect transistor (RADFET) that can be configured to produce alarger threshold voltage shift for a given amount of received orabsorbed dose relative to the sensors 30 positioned in the window of thetargeted treatment volume. The larger voltage shift may increase doseresolution and possibly dose repeatability.

In addition, single-use dosimeters can be optimized to work over a muchlower dose range than multiple use dosimeters. Since the typical per dayfraction for radiation therapy is about 200 cGy, the dosimeter sensor 30can be optimized for accuracy and repeatability over this dose range. A50-500 cGy operating range should meet performance goals while providingadequate flexibility for varying treatment plans. A multiple-sessionfraction dosimeter sensor 30 may require a much larger dose range thatdepends on the number of fractions over which the sensor will operate.As used herein, “disposable” means that the sensor patch is not reusableand can be disposed of or placed in the patient's records.

As shown in FIG. 3A, the indicia can include an alphanumeric identifiersuch as the letter “F” located to be externally visible on the sensorpatches 30. The letter “F” can represent that the sensors are placed ona first side or front of the patient. FIG. 3B illustrates that a secondset of sensors 130′ can be supplied, these sensor patches 30 can belabeled with different indicia, such as 1B, 2B, 3B and the like,representing that they are located at a different location relative tothe first set (such as a second side or back of the patient). Using datafrom opposing outer surfaces can allow an interpolated radiation doseamount to be established for the internal tumor site.

It will be understood that the indicia described above, namely “F” and“B”, are provided herein for exemplary purposes only and that indiciaaccording to embodiments of the present invention are not limited by theexamples provided. Any label, mark, color or the like may be used thatwould serve to distinguish one patch or set of patches from anotherpatch or set of patches without departing from the teachings of thepresent invention. For example, instead of “F” and “B”, the first set ofpatches 130 may be blue and the second set of patches 130′ may be red.Furthermore, the indicia may be, for example, on the sensor patch itselfor on an adhesive covering placed on or over the sensor patch withoutdeparting from the teachings of the present invention.

FIG. 3C illustrates a patient anatomical map 150 that can be used toidentify where each of the sensor patches 30 are placed on the body ofthe patient. The map 150 may be stored in the patient chart or file. Foreach treatment session for which dose monitoring is desired, theclinician can allocate the same sensor patch identifier (“A”, “1F”, etc. . . ) to the same location. The map 150 and/or indicia on the sensorpatches 30 can, in turn, help the clinician consistently identifywhether a particular location may have undue or deficient exposure. Forexample, if sensor patch F1 indicates a low radiation exposure, while F3indicates a relatively high exposure, and the two are positioned in thetargeted beam region, either one or both of the sensor patches 30 is notfunctioning properly, or the radiation beam may need adjustment. Usingsubstantially the same sensor patch position for successive treatmentsessions may allow cumulative radiation dose data to be obtained andcorrelated to provide a more reliable indication of dose. The clinicianmay also draw markings on the patient's skin to help align the sensorpatches 30 in relation thereto over the different treatments sessions.

In certain embodiments, the discrete sensor patches 30 can be arrangedto reside on a common substrate or to be attached to each other so as todefine known or constant distances therebetween (not shown). The sensorpatches 30 may be configured to be at the body temperature of thepatient during use or at room temperature, or temperatures in between.In certain embodiments, to establish a calculated dose amount, atemperature reading may be obtained, assumed, or estimated. In certainparticular embodiments, the temperature may impact the operationalchange if substantially different from that upon which the calibrationdata is established.

In certain embodiments, a first set-up pre-dose verification protocolcan be carried out to deliver a first radiation dose and a firstradiation dose value can be obtained for at least one selected patch toconfirm that the radiation beam focus location is correct or suitable(or whether a sensitive area is receiving radiation). In addition, thesystem can be configured to map a dose gradient by correlating thedetermined radiation dose values at each patch location to theanatomical location on the subject of each patch.

FIG. 4 illustrates an exemplary patient dosimetry form 99, which may be,for example, a paper sheet or computer printable document. The form 99can contain an anatomical map 150 as discussed above with respect toFIG. 3C. Sicel Technologies, Inc. asserts copyright protection for theform illustrated in FIG. 4 and has no objection to reproduction of thepatent document, as it appears in the Patent and Trademark Office patentfile or records, but reserves all other rights whatsoever.

As discussed above, the map 150 may be used to identify and/ormemorialize for the patient record where each of the sensor patches 30are placed on the body of the patient during use. An anatomical map 150can be used to record the specifics of each radiation session and may beplaced in each patient's chart or file to assist the doctor and/orclinician. Patients being treated on an ongoing basis may have multipledosimetry forms 99 in their chart and/or file corresponding to eachtreatment session. As noted above, for each treatment session, theclinician can, as desired, allocate the same sensor patch identifier tothe same location aided by the map 150. As further illustrated in FIG.4, the dosimetry form 99 may further include a dosimetry plan portion152, a measurement data portion 154 and a sensor patch record portion156.

The dosimetry plan portion 152 may include the patient's name, the dateor dates the patient is scheduled for the treatment, the patient'sdoctor, and any information that may be specific to the patient or thepatient's treatment. The measurement data portion 154 may includeinformation such as the date of the treatment and the therapistadministering the treatment on that date. The sensor patch recordportion 156 may include labeled sections 158 (A, B, . . . ) giving eachpatient a discrete identifier which may correspond to sensor patchlocations (A, B, . . . ) with the identifiers indicated on theanatomical map 150. The sensor patch record portion 156 may furtherinclude dosing data, for example, target and measured doses asillustrated in FIG. 4. The sensor patch record portion 156 may furtherinclude the actual sensor patch used on the patient in each of thelabeled sections 158. As shown, the form 99 can include two separatestorage regions, namely a pre and post dose use storage region. Inaddition, the faun 99 can also allow a clinician to indicate whether thesensor patch was held in the entrance and/or exit field.

In certain embodiments, the sensor patch 30 may contain a storage ormemory device 67 (FIGS. 3A, 9B), the storage or memory device on thesensor patches may be accessed to determine dosing information etc. ifthis information fails to be recorded, is misplaced or requiresverification. Furthermore, the memory device 67 included on the sensorpatch 30 may further include the data recorded in the map portion 150,the dosimetry plan portion 152 and the measurement data portion 154 ofthe dosimetry form 99. Accordingly, the memory device 67 on the sensorpatch 30 may serve as an electronic dosimetry patient record form. Itwill be understood that the dosimetry form 99 of FIG. 4 is provided forexemplary purposes only and that the present invention may provide dataand/or hold sensor patches in alternate manners without departing fromthe teachings of the present invention.

FIG. 5A illustrates the use of five primary sensor patches 30 positionedover the targeted treatment region (on the front side of the patient)and one sensor patch 30 s positioned over the heart. FIG. 5B illustratesthree primary sensors 30 located over the back surface proximate thearea corresponding to the underlying tumor site 25.

FIG. 6 illustrates a reader or data acquisition device 75′ according toembodiments of the present invention, in point contact with theunderlying sensor patch 30 in order to detect the amount of radiationthat the sensor patch 30 was exposed to during (or after) the treatmentsession. In certain embodiments, as discussed above, the sensorpatch(es) 30 can be secured to a patient's chart or dosimetry form 150and read after removal from the patient. The reader 75′ illustrated inFIG. 6 may be configured to contact a portion of an electrical circuiton the sensor patch 30 that includes a device that has an operatingcharacteristic or parameter that changes upon exposure to radiation in apredictable manner to allow radiation doses to be determined. The reader75′ can be configured with a probe 75 p that is configured toelectrically contact an electrically conductive probe region on thesensor patch 30 so as to obtain a reading in a “short” time of underabout 30 seconds, and typically in less than about 5-10 seconds, foreach of the sensor patches 30.

Referring now to FIG. 7 a sensor patch 30′ disposed in a reader or dataacquisition device 75″ according to further embodiments of the presentinvention. Sensor patches 30′ according to embodiments of the presentinvention may be adapted to be inserted into the reader 75″. Similarly,the reader 75″ is adapted to receive the sensor patch 30′. As shown, thesensor patch 30′ is formed to include a tab portion 36 that at least aportion of is sufficiently rigid to sustain its shape for properelectrical coupling when inserted into a port 32 in the reader device75″. As illustrated in FIG. 7, the reader 75″ may include a sensor port32 and the sensor patch 30′ may be inserted into the port 32 in thereader 75″ in order to detect the amount of radiation that the sensorpatch 30′ was exposed to. The port 32 can read the sensor patch 30 as itis held in selected orientations in the port 32. The port 32 may beconfigured similar to conventional devices that read, for example,glucose strip sensors and the like. The port 32 illustrated in FIG. 7may contain one or more electrical contacts configured to contact one ormore electrical contacts on the sensor patch 30′ to electrically connectthe reader 75″ to an electrical circuit on the sensor patch 30′. Theelectrical circuit on the sensor patch 30′ includes aradiation-sensitive component that has an operating characteristic orparameter that changes upon exposure to radiation in a predictablemanner to allow radiation doses to be determined. As before, the reader75″ may obtain a reading in under about 30 seconds, and typically inless than about 5-10 seconds, for each of the sensor patches 30.

The reader device 75″ can be held in a portable housing 37. It may bepocket sized and battery powered. In certain embodiments, the readerdevice 75 may be rechargeable. As shown in FIGS. 7, 15A and 15B, thereader 75 may include a display portion 75 d, for example, a liquidcrystal display (LCD), to provide an interface to depict data to thedoctor and/or technician.

The function of the reader device 75 may be incorporated into anyportable device adapted to receive a sensor patch 30 in, for example, asensor port 32. For example, the reader 75 functionality/circuitry couldbe disposed in a personal digital assistant (PDA) that is adapted toinclude a radiation sensor port 32. The reader 75 may further include aremote computer port 33. The port 33 may be, for example, RS 232,infrared data association (IrDA) or universal serial bus (USB), and maybe used to download radiation and/or other selected data from the sensorpatch 30 to a computer application or remote computer. In someembodiments, the sensor patch 30 and the reader device 75 may both beequipped with an RF interface and information may be shared between themwirelessly.

In certain embodiments, as noted above, the sensor patch 30 includes astorage or memory device 67. In these embodiments, the reader 75 may beconfigured to obtain data stored in the memory device 67 of the sensorpatch 30 using, for example, electrical contacts on the reader 75 andthe patch 30, to transfer the data stored in the memory device 67 of thesensor patch 30. This data obtained from the sensor patch memory device67 may, for example, be stored locally on the reader 75 or be downloadedto an application on, for example, a remote computer using a port 33provided in the reader 75. The memory device 67 on the sensor patch 30may serve as a permanent record of the radiation dose and may contain areal time clock such that the obtained data may include a time and datestamp.

FIG. 8A illustrates exemplary embodiments of a sensor patch 30. Asshown, the sensor patch 30 includes a substrate layer 60, a circuitlayer 61, and an upper layer 62 that may be defined by a coating, film,or coverlay material. The substrate layer 60 can be selected such thatit is resilient, compliant, or substantially conformable to the skin ofthe patient. Examples of suitable substrate layer materials include, butare not limited to, Kapton, neoprene, polymers, co-polymers, blends andderivatives thereof, and the like. The underside or bottom of the sensorpatch 30 b may include a releasable adhesive 30 a so as to be able toattach to the skin of the patient. The adhesive 30 a can be a medicalgrade releasable adhesive to allow the sensor patch 30 to be secured tothe skin during the treatment session and then easily removed withoutharming the skin. The adhesive 30 a can be applied to portions, or all,of the bottom surface of the substrate layer 60. In certain embodiments,the underside of the sensor patch 30 b may be free of the adhesive. Inthese embodiments, an adhesive coverlay 30 c 1 (FIG. 9C) may be placedover the body of the sensor patch 30 to secure the sensor patch 30 tothe patient. The adhesive coverlay 30 c 1 may be sized to extend beyondthe outer perimeter of the sensor substrate 60. The adhesive may be on aportion or all of the underside of the coverlay 30 c 1.

In other embodiments, the sensor patch(es) 30 is configured as adiscrete, low profile, compact non-invasive and minimally obtrusivedevice that conforms to the skin of the patient. The sensor patch(es)may be less from about 0.25 to about 1.5 inches long and wide and have athin thickness of from about 1 to about 5 mm or less. As such, thesensor patches 30 can, in certain particular embodiments, be secured tothe patient and allowed to reside thereon for a plurality or all of thesuccessive treatments. For example, the sensor patches 30 can beconfigured to reside on the patient in its desired position for a 1-4week, and typically about a 1-2 week period. In this manner, the samesensor patches 30 can be used to track cumulative doses (as well as thedose at each treatment session). An adhesive may be applied in aquantity and type so as to be sufficiently strong to withstand normallife functions (showers, etc.) during this time. Of course, selectedones of the sensor patches 30 can also be replaced as desired over thecourse of treatment as needed or desired.

In certain embodiments of the present invention, it may be important toattach the sensor patch 30 to the patient so that it makes and retainssnug contact with the patient's skin. Air gaps between the sensor 30 andthe patient's skin may cause complications with respect to obtaining theestimated dosage data. As illustrated in FIGS. 9D and 9E, someembodiments of the present invention include the placement of an overlaymaterial 30 f 1 over the sensor patch 30 to, for example, simulateplacement of the sensor patch 30 beneath the patient's skin. This typeof simulation may help to focus a narrow portion of the radiation beamin proximity to the sensor patch 30 and, therefore, increase thereliability of radiation measurement. Radiation measurement using thesensor subsurface electronics may be optimal at from about 0.5 to about3 cm beneath the patient's skin, but typically is from about 1 to about1.5 cm beneath the patient's skin. Accordingly, the overlay material 30f 1 may be from about 0.5 to about 3 cm thick to simulate subsurfacedepth measurement conditions. The presence of this overlay material 30 f1 may decrease the influence of air gaps between the sensor 30 and thepatient's skin.

The overlay material 30 f 1 may be, for example, a resilient flubberlike or flexible material that will conform to the skin such as anelastomeric or the like. As illustrated in FIG. 9D, the overlay material30 f 1 may be placed between the adhesive coverlay 30 c 1 and the sensorpatch 30 such that the adhesive coverlay 30 c 1 adheres the sensor patch30 and the overlay material 30 f 1 to the patient's skin. As illustratedin FIG. 9E, the overlay material 30 f 1 may be placed over the adhesivecoverlay 30 c 1 and the sensor patch 30. In certain embodiments, theoverlay material may have adhesive properties such that the overlay 30 f1 may be adhered to the patient's skin. The overlay material 30 f 1 mayalso be integrated with the sensor patch 30 without departing from theteachings of the present invention.

Still referring to FIG. 8A, the sensor circuit layer 61 can be attachedto, and/or formed on, the underlying substrate layer 60. The upper layer62 can be configured as a moisture inhibitor or barrier layer that canbe applied over all, or selected portions of, the underlying circuitlayer 61. It is noted that, as shown, the thickness of the layers 60-62are exaggerated for clarity and shown as the same relative thickness,however the thickness of the layers may vary. In certain embodiments,the sensor patch 30 is configured as a low profile, thin device that,when viewed from the side, is substantially planar.

FIG. 8B is a top view of embodiments of a sensor patch 30. As shown, incertain embodiments, the circuit may layer include two conductive probecontacting regions 30 p. During data readings/acquisitions, the probecontacting regions 30 p are configured to provide the connectionsbetween the operating circuitry on the circuit layer 61 and the externalreader. The probe contacting region(s) 30 p can be directly accessibleor covered with a protective upper layer 62. If directly accessible,during operation, the reader 75 can merely press against, contact orclip to the sensor patch 30 to contact the exposed surface of theconductive probe region 30 p to obtain the reading. If covered by anupper layer 62 that is a protective coating or other non-conductiveinsulator material, the clinician may need to form an opening into thecoating or upper layer over the region 30 p so as to be able topenetrate into the sensor patch 30′ a certain depth to make electricalcontact between the probe region 30 p and the probe of the reader 75 p.

FIG. 8C illustrates a probe portion 75 p of the reader 75′ of FIG. 6. Asillustrated, the probe portion 75 p may be configured so that the probe75 p includes, for example, conductive calipers, pinchers, or otherpiercing means, that can penetrate to make electrical contact with theprobe contacting region 30 p of the sensor patch.

FIG. 9A illustrates a top view of embodiments of a circuit layer 61. Asshown, the circuit layer 61 includes the radiation sensitive operativesensor patch circuitry 30 c that is self-contained and devoid ofoutwardly extending or hanging lead wires that connects to anoperational member. The sensor patch circuitry 30 c includes a radiationsensitive device 63 that exhibits a detectable operational change whenexposed to radiation. In certain embodiments, the radiation sensitivedevice 63 is a miniaturized semiconductor component such as a MOSFET.Suitable MOSFETs include RADFETs available from NMRC of Cork, Ireland.In certain embodiments, the MOSFET may be sized and configured to beabout 1-2 mm in width and length. The circuitry 30 c also includes atleast one conductive lead or trace 64 extending from the radiationsensitive device 63 to the conductive probe contacting region 30 p. Inthe embodiment shown, the conductive probe contacting region 30 p is anannular ring. As also shown there are two traces 64 i, 64 o that connectthe device 63 to the ring 30 p. The traces or leads 64′ may be formed,placed, or deposited onto the substrate layer 60 in any suitable mannerincluding, but not limited to, applying conductive ink or paint or metalspray deposition on the surface thereof in a suitable metallic pattern,or using wires. As desired, an upper layer 62 such as described above(such as epoxy) may be formed over the circuit layer 61 (or even theentire sensor patch). The sensor patch 30 may include integrated ElectroStatic Discharge (ESD) protection, the reader 75 may include ESDprotection components, or the user/operator may use ESD straps and thelike during readings.

In particular embodiments, the sensor patch 30 and circuit 30 c can beconfigured with two or more MOSFETS. In embodiments configured to havetwo MOSFETS, one may be positioned over the other on opposing sides ofthe substrate in face-to-face alignment to inhibit orientation influenceof the substrate. (not shown). Additionally, other materials, e.g.,certain epoxies, can be used to both encapsulate the MOSFETs and providefurther scattering influence to facilitate isotropic response of theMOSFETs. In addition, there are well known influences of radiationbackscatter from the surface of patients on whom surface-mounteddosimeters are used. The backscatter effect can be taken into accountwhen calculating an entrance or exit dose or sufficient build-up may beprovided on the top of the dosimeter to promote the equilibration ofscattered electrons. See, Cancer, Principles and Practice of Oncology,3d edition, ed. VT DeVita, S. Hellman, and SA Rosenberg (J B LippincottCo., Phila., 1989), the contents of which are hereby incorporated byreference as if recited in full herein.

FIG. 9B is a top view of further embodiments of a sensor patch 30′ thatincludes a tab portion 36 that is adapted to be received by a reader,for example, reader 75″ illustrated in FIG. 7. As shown, the circuit 30c′ includes a circuit layer 61 that includes at least one electricalcontact 31 shown as a plurality of substantially parallel leads. Duringdata readings/acquisitions, the sensor patch 30′ is inserted into thereader port 32 of the reader 75″ (FIG. 7) and the at least oneelectrical contact 31 is configured to provide the electricalconnections between the operating circuitry on the circuit layer 61 andthe external reader 75″. The electrical contact(s) 31 may be coveredwith a protective upper layer 62 (FIG. 8A). If covered by an upper layer62 that is a protective coating or other non-conductive insulatormaterial, the clinician may need to form an opening into the coating orupper layer over the electrical contact(s) 31 so these contact(s) 31 maymake electrical contact with the reader via sensor port 32 (FIG. 7).

FIG. 9B further illustrates the circuit layer 61 that includes theradiation sensitive operative sensor patch circuitry 30 c′. The sensorpatch circuitry 30 c′ includes a radiation sensitive device 63 thatexhibits a detectable operational change when exposed to radiation andmay include a memory device 67. In certain embodiments, the radiationsensitive device 63 is a miniaturized semiconductor component such as aMOSFET. Suitable MOSFETs include RADFETs available from NMRC of Cork,Ireland. In certain embodiments, the MOSFET may be sized and configuredto be about 1-2 mm in width and length. The circuitry 30 c′ alsoincludes at least one conductive lead or trace 64′ extending from theradiation sensitive device 63 and/or the memory device 67 to the atleast one electrical contact(s) 31. The traces or leads 64′ may beformed, placed, or deposited onto the substrate layer 60 in any suitablemanner including, but not limited to, applying conductive ink or paintor metal spray deposition on the surface thereof in a suitable metallicpattern, or using wires. As desired, an upper layer 62 such as describedabove (such as epoxy) may be formed over the circuit layer 61 (or eventhe entire sensor patch). Each sensor patch 30 may be from about 0.25 toabout 1.5 inches long and wide and have a thin thickness of from about 1to about 5 mm or less.

As discussed above with respect to FIG. 8A, the underside or bottom ofthe sensor patch 30 b may include a releasable adhesive 30 a so as to beable to attach to the skin of the patient. The adhesive 30 a can be amedical grade releasable adhesive to allow the sensor patch 30 to besecured to the skin during the treatment session and then easily removedwithout harming the skin. The adhesive 30 a can be applied to portions,or all, of the bottom surface of the substrate layer 60. Referring nowto FIG. 9C, in certain embodiments, the underside of the sensor patch 30b may be free of the adhesive. As illustrated, an adhesive coverlay 30 c1 may be placed over the entire body of the sensor patch 30 to securethe sensor patch 30 to the patient. As further illustrated, the adhesivecoverlay 30 c 1 may be sized to extend beyond the outer perimeter of thesensor substrate 60 and leave the tab portion 36 of the sensor 30′exposed. The adhesive provided on the underside of the coverlay 30 c 1may be provided on a portion of the coverlay 30 c 1, for example, theportion of the coverlay 30 c 1 contacting the patient's skin outside theperimeter of the sensor substrate 60, or on the entire underside of thecoverlay 30 c 1.

Sensor patches 30 according to embodiments of the present invention maybe provided individually or in sheets containing multiple sensor patches30. In particular, the sensor patches 30 may be fabricated inhigh-density sheets. As used herein, “high density” refers to multiplesensor patches provided on a unitary sheet. High density is intended toencompass very large sheets containing, for example, hundreds orthousands of sensors, as well as, for example, 3×3 regions of these verylarge sheets typically including 6 or more sensors per region. Providingthe sensor patches 30 including memory devices 67, for example EEPROMs,on high density sheets 200 as illustrated in FIGS. 10A and 10B providethe capability of calibrating and/or pre-dosing the entire sheet ofsensor patches 30 at one time. As shown in FIG. 10A, the sheets 200 mayinclude perforations for subsequent separation of the individual sensorpatches 30 from the high density sheet 200. In certain embodiments, thesheet of sensor patches 200 may include from about 30 to about 100sensor patches 30 per sheet. In other embodiments, multiple patches 30may be provided per square inch of the high density sheet 200 and/ormultiple patches 30, typically at least 6 patches, may be provided in a3 by 3 inch region of the high density sheet.

The sensor patches 30 may be calibrated at the factory or OEM. Each ofthe sensor patches 30 or the entire sheet 200 of sensor patches 30 maybe calibrated by providing a wire(s) 205 illustrated in FIG. 10B thatelectrically couples each of the sensor patches 30 on the sheet 200. Forease of reference, only a single electrical line to one sensor is shownon FIG. 10B. The calibration data may be provided to the sensor patches30 through the wire(s) 205 and may be stored in the memory storagedevice 67 of the sensor patch 30. The ability to calibrate a pluralityof sensor patches 30 simultaneously may provide more precision in thedosimetry process and, therefore, possibly more reliable results. Itwill be understood that the sensor patches 30 may each have a dedicatedwire or the sheet can have a calibration line all connected to a commonlead 206 as shown in FIG. 10C that may be used to calibrate and/orpre-dose the sensor patches 30 individually.

As discussed above, the sensor patches 30 may be pre-dosed, i.e. dosedprior to placement on the patient. Dosing a sensor patch may include,for example, setting the amount of radiation to be delivered to apatient and the particular region(s) on the patient to which theradiation should be delivered. This process is typically performed by aphysicist and can be very time consuming. The possibility of accuratelypre-dosing a sensor patch 30 may significantly reduce the need for aphysicist to be involved in the dosimetry confirmation process. In otherwords, using reliable dose patches can reduce the time a physicistexpends to confirm the treatment beam and path dose.

It will be understood that sensor patches 30 adapted to be received by areader 75 are not limited to the configuration illustrated in thefigures provided herein. These figures are provided for exemplarypurposes only and are not meant to limit the present invention. Forexample, the sensor patch 30′ of FIG. 9B can be configured with ageometry that allows it (entirely or partially) to be received by areader 75″. The insertable geometry may take the form of an elongatedtab, one end of the tab containing the radiation sensitive circuitry aswell as the memory and the other end of the tab containing theelectrical contacts for insertion into the reader device (not shown).

As shown in FIG. 11, in certain embodiments, the radiation sensitivedevice 63 is a RADFET. The RADFET can be biased with a gate/drain shortso that it acts as a two-terminal device. FIG. 11 illustrates a portionof the circuit 30 c with a RADFET 63 and two associated reader 75interface or contact points 63I₁, 63I₂. FIG. 12A illustrates a reader 75(upper broken line box) and the circuit 30 c (lower broken line box)with the RADFET 63 configured with a gate to drain short. As shown, thereader 75 can include a RADFET bias circuit 75 b that includes acontrolled current source to allow a voltage reading to be obtainedcorresponding to the threshold voltage of the RADFET.

As shown by the graph in FIG. 12B, changes in surface state chargedensity induced by ionizing radiation causes a shift in thresholdvoltage in the RADFET. FIG. 12B illustrates a radiation response of astandard P210W2 400 nm implanted gate oxide RADFET with lines for 0V(the -0-marked line) and 5V (the line with the -*-markings) irradiationbias responses. To obtain the amount of threshold voltage (“Vth”) shift,the Vth value (zero dose) can be subtracted from the post-irradiationvalue and the calibration curve used to determine radiation dose. Thecalibration curve can be pre-loaded into the controller of the reader ora computer to provide the dose data. In certain embodiments, whenobtaining the readings, the clinician may wear grounding straps toreduce static sensitivity of the circuitry. In certain embodiments, suchas where contact points are exposed, ESD protection may be integratedinto the sensor patch 30 itself.

As shown in FIG. 12A, the Vth change can be measured by determining thechange in applied gate voltage necessary to induce a set current flow.As noted above, the RADFET characterization data can be obtained priorto exposure to radiation (zero dose). Thus, the starting thresholdvoltage of the sensor patch 30 will be known from a priori information(or can be obtained by the clinician prior to placing on the patient orafter on the patient but before radiation exposure) and can be placed inthe reader 75 or computer associated or in communication therewith.

FIG. 13 illustrates the threshold voltage relationship between outputvoltage (voltage) and current Ids (the electrical current, drain-tosource, in microamps) as measured using the output voltage of the readercircuit shown in FIG. 12A. In operation, the reader circuit isconfigured to contact the sensor to provide a constant current source tothe circuit so as to be able measure Vth at a substantially constant orfixed bias condition.

FIGS. 14A and 14B illustrate alternate embodiments of MOSFET basedcircuits 30 c. Each circuit 30 c employs a RADFET pair 63 p (FIG. 14A),63 p′ (FIG. 14B) as the radiation sensitive device 63. The configurationon the left of each of these figures illustrates the irradiationconfiguration and the configuration on the right illustrates the readdose configuration. In the embodiment shown in FIG. 14A, the RADFET pair63 p are differentially biased during irradiation to create differentvoltage offsets. Each of the RADFETs in the pair 63 p ₁, 63 p ₂ can bedifferentially biased during radiation to generate different voltageoffsets when exposed to radiation. Using a pair of RADFETS can reducethe influence of temperature in the detected voltage shift value. Inparticular embodiments, the RADFET pair can be matched (such as takenfrom the same part of the substrate during fabrication) to reduce drifteffects (Vth drift). In certain embodiments, the voltage reading can beobtained with a zero bias state, and/or without requiring wires duringradiation, and/or without requiring a floating gate structure.

In the embodiment shown in FIG. 14B, one of the RADFETs 63 p ₁′ in thepair 63 p is selectively implanted with dopant ions to shift thethreshold voltage (Vth) of that RADFET with respect to the other RADFET63 p ₂′. The ion implantation can be carried out in various manners asknown to those of skill in the art, such as by masking one of the FETswith photoresist to inhibit ions from entering into the gate region. Asis well known, using the proper implant species and/or dopant materialcan increase the FET sensitivity to radiation effects. In certainembodiments of the present invention, a MOSFET (RADFET) pair is used toeffectively provide “differential biasing” without the need to apply anexternal voltage and without the need for a floating gate structure.That is, the MOSFETs can be configured to be individually unbiased andreadings of the two MOSFETs (one at a different threshold voltage value)generates the differential biasing. In particular embodiments, thisradiation sensitive MOSFET pair configuration that does not requirefloating gate structures and/or external voltage can be used inimplantable as well as skin mounted sensors, such as in implantablesensors used as described in U.S. Pat. No. 6,402,689 to Scarantino etal.

FIG. 15A illustrates embodiments of a radiation dose evaluation system15 according to embodiments of the present invention. As shown, thesystem 15 includes a reader 75 and a set of radiation sensor patches130′. The reader 75 may include, for example, the reader 75′ of FIG. 15Bor the reader 75″ of FIG. 15C. The sensor patches 30 can be arranged asa strip of patches 30 held in a single-patient sized package 130 p. Asbefore, the package 130 p may also include bar coded radiationcalibration characterizing data labels 132 for the sensor patches 30and/or a memory 167 in each or selected memory patches 30. The reader75′ as shown in FIG. 15B can include the probe 75 p, an optical wand 75w and a display screen 75 d. The reader 75″ as shown in FIG. 15C caninclude a sensor port 32 and a display screen 75 d. The reader 75 canalso include a RADFET bias circuit 75 b. In certain embodiments, thereader 75 is a portable flat pocket or palm size reader that a cliniciancan carry relatively non-obtrusively in his/her pocket or a similarsized casing.

As shown by the dotted line boxes in FIG. 15A, the reader 75 may hold apower source 78 and plurality of operational software modules including:an optical bar code reader module 76, a zero-dose threshold voltage datamodule 77, a radiation dose conversion module (based on a predeterminedvoltage threshold to radiation dose response curve) 79, and a thresholdvoltage post radiation data module 80.

In operation, the reader 75 can be configured to supply a bias currentto the RADFET by attaching to the sensor patch 30 and electricallycontacting the conductive probe region 30 p or the electrical contacts31. The reader 75 can measure the voltage shift response of the RADFETon the sensor patch 30 and calculate radiation dose based on the shiftand the dose conversion algorithm. The reader 75 can display the resultsto the clinician (such as on an integrated LCD screen 75 d incorporatedinto the body of the reader) and may be configured to download or uploadthe data to another device (such as a computer or computer network) forelectronic record generation or storage.

The dose amount can be calculated for each sensor patch 30 used. Inparticular embodiments, the system can be configured to generate anaverage or weighted average of the dose amount determined over aplurality of the patches. In certain embodiments, where there is a largevariation in values (or if it departs from a statistical noun orpredicted value) the system can be configured to discard that sensorvalue or to alert the clinician of potential data corruption. Of course,much smaller values are predicted in sensitive areas away from thetargeted zone and the system can be configured to evaluate whether thesensor is in a primary location or in a secondary zone as regards theradiation path.

It is noted that features described with respect to one embodiment ofthe sensor, reader and/or system may be incorporated into otherembodiments and the description and illustrations of such features arenot be construed as limited to the particular embodiment for which itwas described.

As will be appreciated by one of skill in the art, the present inventionmay be embodied as a method, data or signal processing system, orcomputer program product. Accordingly, the present invention may takethe form of an entirely hardware embodiment or an embodiment combiningsoftware and hardware aspects. Furthermore, the present invention maytake the form of a computer program product on a computer-usable storagemedium having computer-usable program code means embodied in the medium.Any suitable computer readable medium may be utilized including harddisks, CD-ROMs, optical storage devices, or magnetic storage devices.

The computer-usable or computer-readable medium may be, for example butnot limited to, an electronic, magnetic, optical, electromagnetic,infrared, or semiconductor system, apparatus, device, or propagationmedium. More specific examples (a non-exhaustive list) of thecomputer-readable medium would include the following: an electricalconnection having one or more wires, a portable computer diskette, arandom access memory (RAM), a read-only memory (ROM), an erasableprogrammable read-only memory (EPROM or Flash memory), an optical fiber,and a portable compact disc read-only memory (CD-ROM). Note that thecomputer-usable or computer-readable medium could even be paper oranother suitable medium upon which the program is printed, as theprogram can be electronically captured, via, for instance, opticalscanning of the paper or other medium, then compiled, interpreted orotherwise processed in a suitable manner if necessary, and then storedin a computer memory.

Computer program code for carrying out operations of the presentinvention may be written in an object oriented programming language suchas LABVIEW, Java®, Smalltalk, Python, or C++. However, the computerprogram code for carrying out operations of the present invention mayalso be written in conventional procedural programming languages, suchas the “C” programming language or even assembly language. The programcode may execute entirely on the user's computer, partly on the user'scomputer, as a stand-alone software package, partly on the user'scomputer and partly on a remote computer or entirely on the remotecomputer. In the latter scenario, the remote computer may be connectedto the user's computer through a local area network (LAN) or a wide areanetwork (WAN), or the connection may be made to an external computer(for example, through the Internet using an Internet Service Provider).

FIG. 16 is a block diagram of exemplary embodiments of data processingsystems that illustrate systems, methods, and computer program productsin accordance with embodiments of the present invention. The processor310 communicates with the memory 314 via an address/data bus 348. Theprocessor 310 can be any commercially available or custommicroprocessor. The memory 314 is representative of the overallhierarchy of memory devices containing the software and data used toimplement the functionality of the data processing system. The memory314 can include, but is not limited to, the following types of devices:cache, ROM, PROM, EPROM, EEPROM, flash memory, SRAM, and DRAM.

As shown in FIG. 16, the memory 314 may include several categories ofsoftware and data used in the data processing system 305: the operatingsystem 352; the application programs 354; the input/output (I/O) devicedrivers 358; a radiation estimator module 350; and the data 356. Thedata 356 may include threshold voltage data 340 (zero dose and postirradiation dose levels) which may be obtained from a reader dataacquisition system 320. As will be appreciated by those of skill in theart, the operating system 352 may be any operating system suitable foruse with a data processing system, such as OS/2, AIX, OS/390 orSystem390 from International Business Machines Corporation, Armonk,N.Y., Windows CE, Windows NT, Windows95, Windows98, Windows2000 orWindows XP from Microsoft Corporation, Redmond, Wash., Unix or Linux orFreeBSD, Palm OS from Palm, Inc., Mac OS from Apple Computer, orproprietary operating systems. The I/O device drivers 358 typicallyinclude software routines accessed through the operating system 352 bythe application programs 354 to communicate with devices such as I/Odata port(s), data storage 356 and certain memory 314 components and/orthe image acquisition system 320. The application programs 354 areillustrative of the programs that implement the various features of thedata processing system 305 and preferably include at least oneapplication that supports operations according to embodiments of thepresent invention. Finally, the data 356 represents the static anddynamic data used by the application programs 354, the operating system352, the I/O device drivers 358, and other software programs that mayreside in the memory 314.

While the present invention is illustrated, for example, with referenceto the radiation estimator module 350 being an application program inFIG. 16, as will be appreciated by those of skill in the art, otherconfigurations may also be utilized while still benefiting from theteachings of the present invention.

For example, the radiation estimation module 350 may also beincorporated into the operating system 352, the I/O device drivers 358or other such logical division of the data processing system. Thus, thepresent invention should not be construed as limited to theconfiguration of FIG. 16, which is intended to encompass anyconfiguration capable of carrying out the operations described herein.

In certain embodiments, the radiation estimation module 350 includescomputer program code for estimating radiation dose based on themeasured threshold voltage shift. The I/O data port can be used totransfer information between the data processing system and the readerdata acquisition system 320 or another computer system or a network(e.g., the Internet) or to other devices controlled by the processor.These components may be conventional components such as those used inmany conventional data processing systems that may be configured inaccordance with the present invention to operate as described herein.

While the present invention is illustrated, for example, with referenceto particular divisions of programs, functions and memories, the presentinvention should not be construed as limited to such logical divisions.Thus, the present invention should not be construed as limited to theconfigurations illustrated in the figures but is intended to encompassany configuration capable of carrying out the operations describedherein.

The flowcharts and block diagrams of certain of the figures hereinillustrate the architecture, functionality, and operation of possibleimplementations of probe cell estimation means according to the presentinvention. In this regard, each block in the flow charts or blockdiagrams represents a module, segment, or portion of code, whichcomprises one or more executable instructions for implementing thespecified logical function(s). It should also be noted that in somealternative implementations, the functions noted in the blocks may occurout of the order noted in the figures. For example, two blocks shown insuccession may in fact be executed substantially concurrently or theblocks may sometimes be executed in the reverse order, depending uponthe functionality involved.

FIG. 17 is a block diagram illustration of one embodiment of a reader 75according to the present invention. As shown, the reader 75 includes anoperating system 422, a processor 410, a power source 456, and a useractivation/input module 460. The reader 75 can also include a RADFETinterface module 475 and a sensor patch memory interface module 478. Incertain embodiments, the sensor patch 30 may be configured tocommunicate wirelessly with the reader 75. In these embodiments, theinterface module 475 may be configured to receive wireless signals fromthe sensor patch 30. The reader 75 may optionally include a sensor patchidentifier module 428 to track which sensor patch 30 has a particularradiation dose result. The identifier module 428 may allow the user toinput via an input keypad associated with the reader, an alphanumericidentifier (F1, B1, etc.) for a particular sensor patch prior toobtaining the reading, or a bar code identifier or other automatedidentifier means can be used (such as scanning a bar code label on thesensor and the like).

The reader 75 also includes pre-radiation (zero dose) threshold voltagedata 440, post radiation threshold voltage data 441, and a radiationestimation module 458. The radiation estimation module 458 may also beconfigured to extrapolate to arrive at the radiation dose delivered tothe tumor site. As shown, the reader 75 may also include an optical barcode scanner module 476 to allow the reader to input the characterizingzero dose threshold voltage values by optically reading same. Similarly,calibration data can be entered via the bar the bar code scanner 476 ormemory 67 from the patches 30. Alternatively, the clinician can enterthe desired data in situ as desired.

The foregoing is illustrative of the present invention and is not to beconstrued as limiting thereof. Although a few exemplary embodiments ofthis invention have been described, those skilled in the art willreadily appreciate that many modifications are possible in the exemplaryembodiments without materially departing from the novel teachings andadvantages of this invention. Accordingly, all such modifications areintended to be included within the scope of this invention as defined inthe claims. In the claims, means-plus-function clauses, where used, areintended to cover the structures described herein as performing therecited function and not only structural equivalents but also equivalentstructures. Therefore, it is to be understood that the foregoing isillustrative of the present invention and is not to be construed aslimited to the specific embodiments disclosed, and that modifications tothe disclosed embodiments, as well as other embodiments, are intended tobe included within the scope of the appended claims. The invention isdefined by the following claims, with equivalents of the claims to beincluded therein.

1. A computer program product for evaluating a radiation dose deliveredto a patient, the computer program product comprising: a non-transitorycomputer readable storage medium having computer readable program codeembodied in the medium, the computer-readable program code comprising:computer readable program code for receiving pre-irradiation thresholdvoltage data associated with a plurality of disposable sensor patches;computer readable program code for accepting data from a readerconfigured to electrically serially contact each of the plurality ofdisposable sensors; and computer readable program code for determiningthe voltage threshold shift of the disposable sensor patches afterradiation to determine the radiation exposure.
 2. A computer programproduct according to claim 1, further comprising computer readableprogram code for extrapolating the determined radiation exposureobtained from the sensor patches to estimate a radiation dose deliveredto a tumor site of a patient.
 3. A computer program product according toclaim 1, further comprising computer readable program code for averagingthe dose amount over a plurality of the patches to determine arepresentative radiation dose.
 4. A computer program product accordingto claim 3, further comprising computer readable program code fordiscarding statistically incorrect radiation exposure values.
 5. Acomputer program product according to claim 4, further comprisingcomputer readable program code for alerting of potential data corruptionor discarding dose values that substantially depart from predictedvalues.
 6. A hand-held dose reader device with a circuit having thecomputer program product of claim
 1. 7. A dosimeter radiation sensor forquantifying radiation exposure or dose, comprising a sensor circuit thatincludes a MOSFET pair configuration that does not require floating gatestructures and/or external voltage applied during radiation.
 8. Adosimeter according to claim 7, wherein one of the MOSFET pair isselectively implanted with ions to shift the threshold voltage relativeto the other MOSFET.
 9. A dosimeter according to claim 8, wherein thethreshold voltages of the two MOSFETs in the MOSFET pair are compared todetermine the radiation dose.
 10. A dosimeter according to claim 7,wherein the dosimeter is configured as a surface mounted patch.
 11. Adosimeter according to claim 7, wherein the dosimeter is configured towirelessly communicate with a reader device to obtain measured radiationdata.
 12. A dosimeter according to claim 7, wherein the MOSFET pair isconfigured to be unbiased.
 13. A dosimeter according to claim 7, whereinthe dosimeter is configured to be inserted into a reader andelectrically couple the reader to the dosimeter.
 14. A dose-readerdevice comprising a sensor port that is adapted to receive a sensorpatch, the sensor patch having a tab portion adapted to be inserted intothe sensor port and electrically couple the sensor patch to the readerdevice to provide data associated with an operational parameter in thesensor patch to the reader device.
 15. A dose-reader device according toclaim 14, wherein the dose reader device includes a circuit fortransferring the associated data to a remote computer and/or a computerapplication.
 16. A dose-reader device according to claim 14, furthercomprising a circuit programmably configured to evaluate a radiationdose delivered to a patient using the associated data of the operationalparameter of the sensor patch, wherein the circuit is configured to: (a)obtain pre-irradiation threshold voltage data of a respective sensorpatch; and (b) calculate radiation exposure of the patient using avoltage threshold shift of at least one sensor patch after radiation.17. A dose-reader device according to claim 14, wherein the dose-readerdevice is a personal digital assistant (PDA).